The ability to paint substrates that have low surface tension and are in need of refinishing, such as porcelain sinks and ceramic tile, offers a major cost savings compared to replacing the substrates. Many types of coatings and paints have been tried in the past for this purpose. Most air-dry, ambient curing coatings and paints do not bond well to porcelain or ceramic surfaces. The problem of maintaining adhesion to these surfaces is further complicated by a soapy, hot water environment in which these substrates are often used.
Ambient curing, two-component epoxy and polyurethane paints and coatings have had the best results in the past for this application. Some of these coatings may last for months or even years without failure when there is minimum use of the tub or sink. Their effectiveness is limited, however, when the coating is subjected to the soapy, hot water environment. These coatings fail rapidly and delaminate from the surface in a matter of hours once damaged or cut through ordinary use of the shower, tub or sink. The coating or paint fails when the film is undercut and loses its adhesive bond.
Thus, there is a need for a coating composition that provides a high quality, long-lasting finish that bonds to tough-to-coat substrates having low surface tension including porcelain and glazed ceramic surfaces such as those used in sinks, tubs, and showers.